Blast-furnace offtake



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Patented Sept. 8,1896.

(No Model.)

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W. R'OTTHOFF & M. A. NEELAND. BLAST FURNACE OPP-TAKE.

No. 567,414. Patnted Sept. 8, 1.896.

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UNITED STATES PATENT ()FFICE WILLIAM ROTTHOFF'AND MARVIN A. NEELAND, OFDUQUESNE,

PENNSYLVANIA.

BLAST-FURNACE O'FFTAK'E.

SPECIFICATION forming part of Letters Patent No. 567,414, datedSeptember 8, 1896. Application filed February 25, 1896. I 8011511110.580,673. (No model.)

To all whom it may concern:

Be it known that we, WILLIAM ROTT'HOFF and MARVIN A. NEELAND, ofDuquesne, in the county of Allegheny and State of Pennsylvania, haveinvented a new and useful Improvement in Blast-Furnace Offtakes, ofwhich the following is a full, clear, and exact description, referencebeing had to the accompanying drawings, forming part of thisspecification, in which- Figure 1 is a vertical section upon the line 11 of Fig. 2, showing the upper portion of a blast-furnace provided withour improvement; and Fig. 2 is a top plan view of the same.

Our invention relates to that class of blastfurnaces which are designedto prevent the carrying out with the outgoing current of gases from thetop of the furnace of finelydivided ore-dust from the charge. In the useof the so-called Mesaba ores,which are in a finely-divided condition,great difficulty has been found by reason of the ore being carried offwith the escaping gas into the fiues and passages through which the gastravels and into the combustion-chambers of the hot-blast This actionresults not only in loss of ore, but in filling up the flues andpassages, thus decreasing their efficiency and necessitating frequentcleaning. To do away with this difliculty, it has been proposed to usean annular pipe surrounding the furnace I and having a series ofgas-outlets leading thereto, the down-comer'being connected to thispipe; and our invention consists in certain features of the annularpipe, as hereinafter more fully described, and set forth in the claims.

In the drawings, 2 represents the upper portion of the blast-furnacewall, this wall having an annular series of inclined outlets 3 thereinfor the outgoing gases, from which outlets extend branch pipes 4, whichlead to an inclined annular pipe 5, which surrounds the upper part ofthe furnace. These branch pipes are preferably provided withexplosion-doors 6 and lead downwardly to the bustle-pipe below them, thedown-comer 7 connecting with the annular pipe at its lowermost point.

8 is the bleeder for the surplus gases.

As shown in Fig. 2,,the annular pipe 5 is not continuous, but on theside of the furnace opposite to that at which the downcomer is attachedit is cut in two and the separated ends provided with suitable closures9 9. It will be noticed that each por-. tion of the bifurcated annularpipe is gradually increased in cross-sectional area from the closed endportion to the lowest point therein, so as to provide for the increasedamount of dust and volume of gases therein. The outlets 3 in thefurnace-wall are inclined inwardly, so that dust lodging therein mayslide back into the furnace, and theannular pipe 5 is also inclined, soas to allow the dust settling therein to slide down into the downcomer,whence it passes to the dust-catcher.

The advantages of our invention will be apparent to those skilled in theart, since the liability to loss of ore-dust and clogging up of thepassages is greatly lessened. The gasoutlets may be spaced as desiredand any desirable number may be employed,and many other variations maybe made without departing from our invention, since We claim 1. Ablast-furnace, having an inclined annular pipe about its upper portion,a downcomer connected to said pipe, and an. annular series ofgas-outlets provided with branch pipes leading to said annular pipe;substantially as described. 7

2. A blast-furnace having in its upper portion an annular series ofgas-outlets and an inclined annular pipe to which they are connected,said pipe being connected on one side to the down-comer and having agradually increasing-cross-sectional area from the opposite side of thefurnace toward the down comer; substantially as described.

In testimony whereof we have hereunto set our hands. s

WILLIAM ROTTHOFF.

MARVIN A. NEELAND.

\Vitnesses:

G. I. HoLnsnIP, H. M. OoRwIN.

